May 3 (Bloomberg) -- Marathon Petroleum Corp. is unable to
load oil from a barge dock on the Mississippi River at Wood
River, Illinois, which may depress Canadian oil prices if
repairs are lengthy.

The unloading arm at the dock was damaged early today when
a barge it was filling with crude was struck by other vessels in
the river that became unmoored, Shane Pochard, a Findlay, Ohio-based spokesman for the company, said in a phone interview.
Repairs will begin soon.

The dock probably loads 40,000 barrels of heavy Canadian
crude a day onto barges that travel down the Mississippi River
to Marathon’s 460,000-barrel-a-day Garyville refinery in
Louisiana, said Andy Lipow, president of Lipow Oil Associates
LLC in Houston. Pochard declined to comment on dock rates.

“A lengthy outage would impact Canadian heavy prices,”
Lipow said. “It depends on how much storage Marathon has on
site and when their batches are coming in.”

At about 12:30 a.m., about 20 barges became unmoored when
they were struck by a tow moving south on the river, said
Lieutenant Colin Fogarty, a St. Louis-based public affairs
officer for the U.S. Coast Guard.

One of those barges collided with a Kirby Corp.-owned
vessel that was being loaded with fuel at the Marathon dock,
causing a spill from the cargo hose, Amy Husted, a spokeswoman
for Kirby, said in a statement.

Differing Estimates

Kirby estimated that three barrels of crude spilled into
the river. The Coast Guard’s estimate was eight barrels.

The Coast Guard shut down a portion of the river while it
collected the loose barges and reopened it before 6 a.m. local
time, Fogarty said. He said the Coast Guard is surveying damage
to facilities and barges and assessing the environmental damage
to the river.

“The Mississippi River is an incredibly unique
environment,” he said. “It’s moving at about 12 miles per
hour, and there’s so much sediment in there, it can chew up
crude oil the way the ocean cannot. That will go a way to
mitigating the crude oil, but it makes it more difficult for us
to determine where it will wash up on shore.”